Oceans Acidifying 10x Faster Than During Last Massive Marine Extinction

The TreeHugger archives are filled to the brim with stories about ocean acidification and the potential future effects of it, but here's a quick one on just how fast today's oceans are changing and how it fits into historic (and catastrophic) ocean changes. Yale Environment 360 details some new research into what happened 55 million years ago during the Paleocene-Eocene thermal maximum, the last time the world's oceans acidified quickly:At that time some 6.8 trillion tons of carbon entered the atmosphere over a period of 10,000 years. The exact cause isn't known for sure, but it caused temperatures to rise 5-9°C and many deep-sea species to go extinct, possibly because the water's pH became too low.

Wanting to compare the conditions during the PETM and today, scientists from the University of Bristol set up simulations of the conditions now and then and adjusted the amount of CO2 in the atmosphere: 6.8 trillion tons over 10,000 years and then 2.1 trillion tons over a few centuries to represent conservative estimates of modern carbon emissions.

In doing so they determined that acidification is happening ten times faster today than it did during the PETM. In the past 200 years ocean pH has increased 30%, an increase of 0.1pH units.

As for future impact, lead author Andy Ridgwell states with typical scientific understatement, "We can't say things for sure about impacts on ecosystems, but there is a lot of cause for concern."